A monohydrated N-(1-iminoethyl)acetamidine nickel complex, a synthesis method and its application in supercapacitors

Abstract

The invention discloses a monohydrated N-(1-iminoethyl)acetamidine nickel complex, a synthesis method and an application thereof in a supercapacitor: the unit cell of the complex contains a four-coordinated nickel cation, two N-(1-iminoethyl)acetamidine anions and a free water molecule, and the unit cell structure is shown in formula (I); the preparation method comprises the following steps: (1) adding Ni(CH3COO)2·4H2O to an acetonitrile solvent, stirring at 25°C for 5-15min until completely dissolved, to obtain a mixed solution; (2) subjecting the mixed solution obtained in step (1) to a solvent thermal reaction at 100-140°C for 90-130h, filtering and washing, to obtain a single crystal-grade monohydrated N-(1-iminoethyl)acetamidine nickel complex, with a yield of 73-81%. The invention has the advantages of simple process, low cost, easy control of chemical reactants, good repeatability, high yield, excellent superelectric performance and the like. #imgabs0#

Description

Technical Field

[0001] The invention belongs to the field of metal complexes, and in particular relates to a monohydrated N-(1-iminoethyl)acetamidine nickel complex, a synthesis method and application thereof in supercapacitors. Background Art

[0002] Supercapacitors can be classified differently according to the energy storage mechanism, electrode materials and electrolyte types. According to the different storage mechanisms, they can be divided into double-layer capacitors and pseudocapacitors. According to the different electrode materials used, they can be divided into metal oxide supercapacitors, carbon-based supercapacitors, polymer supercapacitors and hybrid supercapacitors. Double-layer capacitors mainly use carbon materials with high specific surface area and small internal resistance; while pseudocapacitors mainly use transition metal oxides, hydrate materials and doped polymers, etc.

[0003] According to the classification of electrolytes, they can be divided into aqueous electrolyte capacitors and non-aqueous electrolyte capacitors. Electrode materials are one of the core factors affecting the performance of electrochemical capacitors and are a hot topic in current electrochemical capacitor research. It is the material basis for the electrode to store charge and generate capacitance, and its own electrochemical properties directly affect the electrochemical properties of supercapacitor devices. At present, traditional electrochemical capacitor electrode materials are mainly divided into three categories: carbon-based materials, metal oxides, and conductive polymer materials. However, these three materials have their own disadvantages.

[0004] In order to maximize the performance of capacitors with better power density, energy density and service life, researchers are mostly committed to studying materials with excellent conductivity, large specific surface area and improved electrolyte wettability. Metal complexes, as a new type of material, have large specific surface area, adjustable pore size and abundant redox metal centers, which can meet the above two conditions at the same time. Therefore, they have become a research hotspot in the development and application of supercapacitor electrode materials in recent years. Summary of the invention

[0005] In view of the deficiencies of the prior art, the object of the present invention is to provide a monohydrated N-(1-iminoethyl)acetamidine nickel complex, a synthesis method and its application in supercapacitors.

[0006] The technical solution of the present invention is summarized as follows:

[0007] A monohydrated N-(1-iminoethyl)acetamidine nickel complex: the unit cell of the complex contains a four-coordinated nickel cation, two N-(1-iminoethyl)acetamidine anions and a free water molecule, and the unit cell structure is shown in formula (I):

[0008]

[0009] A method for synthesizing a monohydrated N-(1-iminoethyl)acetamidine nickel complex comprises the following steps: under high temperature and high pressure, acetonitrile undergoes an in-situ trimerization reaction under the catalysis of nickel ions to generate N-(1-iminoethyl)acetamidine, which is then further reacted with nickel ions to form a monohydrated N-(1-iminoethyl)acetamidine nickel complex with nickel ions as the central ion; the method specifically comprises the following steps:

[0010] (1) Add Ni(CH3COO)2·4H2O to acetonitrile solvent and stir at 25°C for 5-15 min until it is completely dissolved to obtain a mixed solution;

[0011] (2) The mixed solution obtained in step (1) is transferred to a polytetrafluoroethylene-lined reactor, and subjected to a solvent thermal reaction at 100-140° C. for 90-130 h, filtered, and washed to obtain a single crystal-grade monohydrated N-(1-iminoethyl)acetamidine nickel complex with a yield of 73-81%;

[0012] The reaction equation in step (2) is:

[0013]

[0014] Furthermore, the usage ratio of Ni(CH3COO)2·4H2O and acetonitrile solvent is (0.248-0.75) g:(10-20) mL.

[0015] The monohydrated N-(1-iminoethyl)acetamidine nickel complex prepared by the synthesis method is used in supercapacitors.

[0016] Furthermore, monohydrated N-(1-iminoethyl)acetamidine nickel complex is used as active material, acetylene black is used as conductive agent, and polytetrafluoroethylene emulsion is used as adhesive. After being evenly ground, it is loaded on a foamed nickel substrate and vacuum dried at 60-70°C for 12-24h to obtain a supercapacitor electrode material.

[0017] Furthermore, the mass ratio of the monohydrated N-(1-iminoethyl)acetamidine nickel complex, acetylene black, and polytetrafluoroethylene emulsion is 8:(1-3):1.

[0018] Furthermore, when the scanning voltage rate is 10 mV / s, the specific capacitance of the supercapacitor electrode material reaches 850.5 F / g;

[0019] When the scanning voltage speed increases from 10 mV / s to 20 mV / s, the specific capacitance retention rate of the supercapacitor electrode material reaches 97.9%;

[0020] Under the conditions of 6 mol / L KOH electrolyte and current density of 1 A / g, after 1000 charge and discharge cycle tests, the capacitance retention rate of the supercapacitor electrode material is ≥97.0%.

[0021] Beneficial effects of the present invention:

[0022] (1) The present invention uses Ni(CH3COO)2·4H2O and acetonitrile solvent to synthesize a monohydrated N-(1-iminoethyl)acetamidine nickel complex having a novel chemical structure and spatial configuration of a tetracoordinate nickel-copper complex for the first time by a solvothermal method. When the complex is used as an electrode material, it has the advantages of high capacity, good cycle stability, mild conditions, reusability, economy and environmental protection in supercapacitor tests.

[0023] (2) The synthesis method of the present invention has the advantages of simple process, low cost, easy control of chemical reactants, good repeatability, high product yield and excellent superelectric performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The steric configuration diagram of the monohydrated N-(1-iminoethyl)acetamidine nickel complex synthesized by the present invention;

[0025] Figure 2 This is a graph showing the supercapacitor performance of an electrode material prepared using a monohydrated N-(1-iminoethyl)acetamidine nickel complex in Example 4;

[0026] Figure 3 This is a cycle stability diagram of the electrode material prepared using the monohydrated N-(1-iminoethyl)acetamidine nickel complex in Example 4;

[0027] Figure 4 The present invention is a flow chart of the synthesis method of the monohydrated N-(1-iminoethyl)acetamidine nickel complex. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0029] The present invention provides a monohydrated N-(1-iminoethyl)acetamidine nickel complex of an embodiment: the unit cell of the complex comprises a tetracoordinated nickel cation, two N-(1-iminoethyl)acetamidine anions and a free water molecule, and the unit cell structure is shown in formula (I):

[0030]

[0031] This embodiment provides a method for synthesizing a hydrated N-(1-iminoethyl)acetamidine nickel complex. Under high temperature and high pressure, acetonitrile undergoes an in-situ trimerization reaction under the catalysis of nickel ions to generate N-(1-iminoethyl)acetamidine, which further reacts with nickel ions to form a monohydrated N-(1-iminoethyl)acetamidine nickel complex with nickel ions as the central ion. Specifically, the method comprises the following steps:

[0032] (1) Add Ni(CH3COO)2·4H2O to acetonitrile solvent and stir at 25°C for 5-15 min until it is completely dissolved to obtain a mixed solution;

[0033] (2) The mixed solution obtained in step (1) is transferred to a polytetrafluoroethylene-lined reactor, and subjected to a solvent thermal reaction at 100-140° C. for 90-130 h, filtered, and washed to obtain a single crystal-grade monohydrated N-(1-iminoethyl)acetamidine nickel complex with a yield of 73-81%;

[0034] The reaction equation in step (2) is:

[0035]

[0036] The usage ratio of Ni(CH3COO)2·4H2O and acetonitrile solvent is (0.248-0.75) g:(10-20) mL.

[0037] The monohydrated N-(1-iminoethyl)acetamidine nickel complex of this embodiment is applied to a supercapacitor: the monohydrated N-(1-iminoethyl)acetamidine nickel complex is used as an active material, acetylene black is used as a conductive agent, and polytetrafluoroethylene emulsion is used as a binder. The mass ratio of the monohydrated N-(1-iminoethyl)acetamidine nickel complex, acetylene black, and polytetrafluoroethylene emulsion is 8:(1-3):1. After being uniformly ground, the mixture is loaded on a foamed nickel substrate and vacuum dried at 60-70°C for 12-24h to obtain a supercapacitor electrode material.

[0038] Example 1

[0039] A method for synthesizing a monohydrated N-(1-iminoethyl)acetamidine nickel complex comprises the following steps:

[0040] (1) Add 0.248 g of analytical grade Ni(CH3COO)2·4H2O to 10 mL of analytical grade acetonitrile solvent and stir at 25°C for 5 min until the reactant is completely dissolved to obtain a clear and transparent mixed solution;

[0041] (2) The mixed solution obtained in step (1) was transferred to a polytetrafluoroethylene-lined reactor, and subjected to a solvent thermal reaction at 100° C. for 90 h. After cooling to room temperature of 25° C., the reactor was opened, filtered, and washed with anhydrous acetonitrile to obtain a single crystal monohydrated N-(1-iminoethyl)acetamidine nickel complex with a yield of 73%.

[0042] The monohydrated N-(1-iminoethyl)acetamidine nickel complex synthesized in Example 1 was characterized by X-ray single crystal diffraction, infrared spectroscopy, mass spectrometry, and nuclear magnetic resonance hydrogen / carbon spectra to confirm that its structural formula is as shown in formula (I):

[0043]

[0044] Example 2

[0045] A method for synthesizing a monohydrated N-(1-iminoethyl)acetamidine nickel complex comprises the following steps:

[0046] (1) Add 0.496 g of analytical grade Ni(CH3COO)2·4H2O to 15 mL of analytical grade acetonitrile solvent and stir at 25°C for 10 min until the reactant is completely dissolved to obtain a clear and transparent mixed solution;

[0047] (2) The mixed solution obtained in step (1) was transferred to a polytetrafluoroethylene-lined reactor, and subjected to a solvent thermal reaction at 120° C. for 120 h. After cooling to room temperature of 25° C., the reactor was opened, filtered, and washed with anhydrous acetonitrile to obtain a single crystal-grade monohydrated N-(1-iminoethyl)acetamidine nickel complex with a yield of 76%.

[0048] Example 3

[0049] A method for synthesizing a monohydrated N-(1-iminoethyl)acetamidine nickel complex comprises the following steps:

[0050] (1) Add 0.750 g of analytical grade Ni(CH3COO)2·4H2O to 20 mL of analytical grade acetonitrile solvent and stir at 25°C for 15 min until the reactant is completely dissolved to obtain a clear and transparent mixed solution;

[0051] (2) The mixed solution obtained in step (1) was transferred to a polytetrafluoroethylene-lined reactor, and subjected to a solvent thermal reaction at 140° C. for 130 h. After cooling to room temperature of 25° C., the reactor was opened, filtered, and washed with anhydrous acetonitrile to obtain a single crystal-grade monohydrated N-(1-iminoethyl)acetamidine nickel complex with a yield of 81%.

[0052] Example 4

[0053] A supercapacitor electrode material was prepared using the monohydrated N-(1-iminoethyl)acetamidine nickel complex prepared in Example 1: the monohydrated N-(1-iminoethyl)acetamidine nickel complex prepared in Example 1, acetylene black, and polytetrafluoroethylene emulsion were evenly ground in a mass ratio of 8:1:1, loaded on a foamed nickel substrate, and vacuum dried at 70°C for 12 h to obtain a supercapacitor electrode material.

[0054] Electrochemical performance of the supercapacitor electrode material prepared by using the monohydrated N-(1-iminoethyl)acetamidine nickel complex in Example 4 was measured.

[0055] (1) Supercapacitor performance test: Figure 2 The discharge curves of the electrode material prepared in Example 4 in 6 mol / L KOH electrolyte at different scanning voltage speeds on an electrochemical workstation with a potential window range of 0-0.40 V. Figure 3 It can be seen that when the scanning voltage speed is 10mV / s, the specific capacitance of the electrode material reaches 850.5F / g, indicating that the electrode material has the potential to be used as a supercapacitor. Figure 3 It can be seen that when the scanning voltage speeds are 10mV / s, 20mV / s, 50mV / s, 70mV / s, and 100mV / s, the specific capacitances are 850.5F / g, 832.7F / g, 814.1F / g, 797.5F / g, and 700.4F / g, respectively. When the scanning voltage speed increases from 10mV / s to 20mV / s, the specific capacitance retention rate of the supercapacitor electrode material prepared in Example 4 is as high as 97.9%.

[0056] (2) Cycle stability test: On an electrochemical workstation, the electrode material prepared in Example 4 was placed in a 6 mol / L KOH electrolyte and subjected to 1000 charge and discharge cycle tests at a current density of 1 A / g.

[0057] Figure 3 The cycle stability diagram of the supercapacitor electrode material prepared in Example 3: Figure 3 It can be seen that after 1000 charge and discharge cycle tests, the capacitance retention rate of the supercapacitor electrode material prepared in Example 4 is ≥97.0%.

[0058] In summary, combined with Figure 2-3 It can be seen that the monohydrated N-(1-iminoethyl)acetamidine nickel complex synthesized in Examples 1-3 has electrochemical properties of high capacity and stable cycle, and has extremely high research and application prospects in supercapacitor electrode materials.

[0059] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A monohydrated N-(1-iminoethyl)acetamidine nickel complex, characterized in that: The unit cell of the complex contains a four-coordinated nickel cation, two N-(1-iminoethyl)acetamidine anions and a free water molecule, and its unit cell structure is shown in formula (I):

2. A method for synthesizing the monohydrated N-(1-iminoethyl)acetamidine nickel complex according to claim 1, characterized in that: Under high temperature and high pressure, acetonitrile undergoes an in-situ trimerization reaction under the catalysis of nickel ions to generate N-(1-iminoethyl)acetamidine, which further reacts with nickel ions to form a monohydrated N-(1-iminoethyl)acetamidine nickel complex with nickel ions as the central ion; specifically, the following steps are included: (1) Add Ni(CH3COO)2·4H2O to acetonitrile solvent and stir at 25°C for 5-15 min until it is completely dissolved to obtain a mixed solution; (2) The mixed solution obtained in step (1) is transferred to a polytetrafluoroethylene-lined reactor, and subjected to solvent thermal reaction at 100-140° C. for 90-130 h, filtered, and washed to obtain a single crystal monohydrated N-(1-iminoethyl)acetamidine nickel complex with a yield of 73-81%.

3. The method for synthesizing the monohydrated N-(1-iminoethyl)acetamidine nickel complex according to claim 2, characterized in that: The usage ratio of Ni(CH3COO)2·4H2O and acetonitrile solvent is (0.248-0.75) g:(10-20) mL.

4. Use of the monohydrated N-(1-iminoethyl)acetamidine nickel complex prepared by the synthesis method according to any one of claims 2 to 3 in supercapacitors.

5. The use according to claim 4, characterized in that: Monohydrated N-(1-iminoethyl)acetamidine nickel complex is used as active material, acetylene black is used as conductive agent, polytetrafluoroethylene emulsion is used as adhesive, after being evenly ground, loaded on a foam nickel substrate, and vacuum dried at 60-70°C for 12-24h to obtain a supercapacitor electrode material.

6. The use according to claim 5, characterized in that: The mass ratio of the monohydrated N-(1-iminoethyl)acetamidine nickel complex, acetylene black and polytetrafluoroethylene emulsion is 8:(1-3):

1.

7. The use according to claim 5 or 6, characterized in that: When the scanning voltage rate is 10 mV / s, the specific capacitance of the supercapacitor electrode material reaches 850.5F / g; When the current density increases from 10 mV / s to 20 mV / s, the specific capacitance retention rate of the supercapacitor electrode material reaches 97.9%; Under the conditions of 6 mol / L KOH electrolyte and current density of 1 A / g, after 1000 charge and discharge cycle tests, the capacitance retention rate of the supercapacitor electrode material is ≥97.0%.

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